JNI-111 Update Makefile.conf and build.gradle

Makefile.conf: point to pep-engine sequoia branch instead of the fork.
build.gradle: Upgrade to match with latest android gradle plugin.

android/build.gradle

@@ -2,7 +2,7 @@
 
 def pEpEngineSrc = hasProperty('pEpEngineSrc') ? pEpEngineSrc : "../../pEpEngine"
 def buildAutomatic = hasProperty('buildAutomatic') ? buildAutomatic : "true"
-def threadsToUse = hasProperty('threadsToUse') ? threadsToUse : 2
+def threadsToUse = hasProperty('threadsToUse') ? threadsToUse : 1
 
 def pEpEngineDB = new File(new File(pEpEngineSrc), 'db')
 
@@ -12,7 +12,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.3'
+        classpath 'com.android.tools.build:gradle:4.0.0'
     }
 }
 
@@ -26,14 +26,13 @@ allprojects {
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 30
-    buildToolsVersion '28.0.3'
 
     defaultConfig {
         minSdkVersion 19
-        targetSdkVersion 27
+        targetSdkVersion 30
-        versionCode 1
+        versionCode 2
-        versionName "1.0"
+        versionName "2.1.0-RC5"
 
         externalNativeBuild {
             ndkBuild {
@@ -145,6 +144,7 @@ android {
         from file(new File(pEpEngineDB, 'system.db'))
         into 'assets'
     }
+    ndkVersion '21.0.6113669'
 
     if(buildAutomatic == "true") {
         buildpEpEngineSystemDB.dependsOn(buildExternal)

android/external/Makefile.conf

@@ -20,7 +20,7 @@ NETTLE_VERSION=3.4.1
 
 ### Git deps repos
 EXTERNAL_GIT_REPOS += libetpan|https://github.com/fdik/libetpan.git?HEAD
-EXTERNAL_GIT_REPOS += sequoia|https://gitlab.com/husspEp/sequoia.git?80cffd395147bc76c3d763618545e66dfe977ac1
+EXTERNAL_GIT_REPOS += sequoia|https://gitlab.com/sequoia-pgp/sequoia.git?b5b783f58c9b6fdb26163cb7b236ee71cfef339e
 
 ### Common variables
 #### Source code targets

android/src/foundation/pEp/jniadapter/AndroidHelper.java

@@ -28,7 +28,7 @@ public class AndroidHelper {
     private static File tmpDir;
         
     // TODO : Increment when needed.
-    public static int ENGINE_VERSION_CODE = 3896;
+    public static int ENGINE_VERSION_CODE = 4768;
 
     private static File shareDir;